نتایج جستجو برای: ratio of valley

تعداد نتایج: 21182691  

1997
K. JERRY ALLWINE XINDI BIAN DAVID WHITEMAN HAROLD W. THISTLE

VALDRIFT (valley drift) is a valley atmospheric transport, diffusion, and deposition model. The model is phenomenological—that is, the dominant meteorological processes governing the behavior of the valley atmosphere are formulated explicitly in the model, although in a highly parameterized fashion. The key meteorological processes treated are 1) nonsteady and nonhomogeneous along-valley winds ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم کشاورزی و منابع طبیعی ساری - دانشکده کشاورزی و منابع طبیعی 1393

زمین لغزش به عنوان یکی از مخاطرات طبیعی مهم هر ساله موجب خسارت های فراوان مالی، جانی و تخریب منابع طبیعی می شود. از این رو بررسی هر چه بیشتر این مخاطرات از الزام های اجتناب ناپذیر حیات آینده بشری می باشد. در پژوهش حاضر، چگونگی بررسی پتانسیل وقوع زمین لغزش و تولید نقشه حساسیت زمین لغزش در سیستم اطلاعات جغرافیایی گرد آوری گشته و به عنوان مطالعه موردی، جاده ساری - کیاسر در نظر گرفته شد و هفده پارا...

Journal: :Physical review letters 2006
O Gunawan Y P Shkolnikov K Vakili T Gokmen E P De Poortere M Shayegan

We report direct measurements of the valley susceptibility, the change of valley population in response to an applied symmetry-breaking strain, in an AlAs two-dimensional electron system. As the two-dimensional density is reduced, the valley susceptibility dramatically increases relative to its band value, reflecting the system's strong electron-electron interaction. The increase has a remarkab...

Journal: :Physical review letters 2014
Y J Jo Joonbum Park G Lee Man Jin Eom E S Choi Ji Hoon Shim W Kang Jun Sung Kim

We report the valley-selective interlayer conduction of SrMnBi(2) under in-plane magnetic fields. The c-axis resistivity of SrMnBi(2) shows clear angular magnetoresistance oscillations indicating coherent interlayer conduction. Strong fourfold variation of the coherent peak in the c-axis resistivity reveals that the contribution of each Dirac valley is significantly modulated by the in-plane fi...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2016
Lu Xie Xiaodong Cui

Manipulating spin polarization of electrons in nonmagnetic semiconductors by means of electric fields or optical fields is an essential theme of the conceptual nonmagnetic semiconductor-based spintronics. Here we experimentally demonstrate an electric method of detecting spin polarization in monolayer transition metal dichalcogenides (TMDs) generated by circularly polarized optical pumping. The...

2016
Wei Luo L. Sheng B. G. Wang D. Y. Xing

We propose to realize adiabatic topological spin and valley pumping by using silicene, subject to the modulation of an in-plane ac electric field with amplitude Ey and a vertical electric field consisting of an electrostatic component and an ac component with amplitudes and . By tuning and , topological valley pumping or spin-valley pumping can be achieved. The low-noise valley and spin current...

2016
T. Sota K. Suzuki

We have theoretically studied the ultrasonic attenuation of heavily doped semiconductors with a single-valley or a many-valley in the weakly localized regime. The following has been found. A contribution from quantum correction terms to the attenuation coefficient Aa decreases with increasing temperature. In the many-valley case Aa decreases with increasing the strength of the intervalley scatt...

2006
Lisa Valdivia David Nix Mark Wright Elizabeth Lindberg Timothy Fagan Donald Lieberman T'Prien Stoffer Neil M. Ampel John N. Galgiani

The early manifestations of coccidioidomycosis (valley fever) are similar to those of other causes of community-acquired pneumonia (CAP). Without specific etiologic testing, the true frequency of valley fever may be underestimated by public health statistics. Therefore, we conducted a prospective observational study of adults with recent onset of a lower respiratory tract syndrome. Valley fever...

2005
Patricia F. McDowell

Like many montane rivers in the western U. S., the Middle Fork of the John Day River is characterized by alternating narrowand wide-valley segments. Although the river has a low gradient (generally < 0.01) alluvial channel, changes in valley width exert a clear infl uence on channel morphology. A spatial hierarchical model of channel morphology was applied to the Middle Fork to understand reach...

Journal: :Physical review letters 2007
Di Xiao Wang Yao Qian Niu

We investigate physical properties that can be used to distinguish the valley degree of freedom in systems where inversion symmetry is broken, using graphene systems as examples. We show that the pseudospin associated with the valley index of carriers has an intrinsic magnetic moment, in close analogy with the Bohr magneton for the electron spin. There is also a valley dependent Berry phase eff...

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